In process engineering, the use of computer based models to develop and evaluate new processes, design and retrofit plants, and optimize the operation of existing plants is rapidly becoming a standard. At every stage of process design, development and operation, rigorous models generated by process simulation software systems can be used to make better engineering and business decisions.
In a process simulation software system the performance of a process industry plant in which there is a continuous flow of materials and energy through a network of process units is simulated. Typically, the process simulation software features computer models which allow process engineers to simulate the operation of various pieces of equipment used in a proposed or existing manufacturing process. The end results from the simulation software system provide a showing of the simulated performance of the plant under various conditions and an estimate of the capital and operating costs of the plant and its profitability.
The ultimate result of the process simulation is a shortened design process and often an improved design in addition to other benefits depending on the stage of process development. For an existing plant, simulation is used to improve the operation, to reduce raw material and energy requirements and to de-bottleneck the process. In research and development, the simulation output is used to study alternative processing schemes, to scale-up the process, and to interpret pilot plant data. For the design of a new plant, the computer based models are used to optimize the design and reduce capital and operating costs. In addition, the simulation reduces the start-up risks for companies that produce high performance, high profit products such as food additives and specialty chemicals. For example, if a company is in the petrochemical business, there are numerous engineering calculations that must be made in determining what type and size of equipment should be used, and what mixture of feed stocks should be used in the manufacturing process. The process simulation system enables the chemical engineer to perform those calculations under many different conditions.
The foregoing benefits provide substantial economic savings from bringing new products to market faster, from designing plants that require less capital investment and cost less to operate, and from reducing manufacturing costs in existing facilities.
In order to use a process simulation system, generally a user first sketches a flowsheet diagram or description of the desired manufacturing process. From that information, the user inputs into the computer the feed stream composition and flows, major equipment items in the plant, and the interconnections between pieces of equipment that result in the flow of materials or energy between process units. From the input, the computer translates the data into a specially formatted computer file, runs the simulation software program on the computer file and generates a report. The report shows the simulated performance of the plant, including the composition, flow and properties of all internal and product streams, and size and performance of individual process units. A report can also be produced to estimate complete project economics, capital and operating costs of the plant and profitability.
The information that the user inputs to the computer from his initial flowsheet diagram is often complex and lengthy extending from chemical components, to physical properties and operating specifications of individual model units, to parameters of chosen pieces of equipment, and inlet stream variables. Dependencies between specified elements and disallowed combinations often become lost in the voluminous and complex information. Hence, a major problem with the use of rigorous computer based models has been the time and effort required for process engineers to prepare the input and correctly specify all the information and data required. The use of the input language by its nature requires knowledge and experience to use it most effectively. Thus, the process engineer has to make frequent reference to the input manual particularly when learning how to use the simulation system or resort to overly simplistic models which greatly underutilizes the potential of the process simulation software system.
Accordingly, there is a need to aid process engineers in providing correct input to process simulation software systems.